Korn frontman Jonathan Davis is unleashing the mother of all conspiracy theories -- President Obama's secret agenda to become a tyrannical dictator with Miley Cyrus, Justin Bieber and Kanye West's assistance! We asked Davis about his band's new "Spike in My Veins" music video -- which is filled with clips of Miley and other pop culture phenoms -- and suddenly it was all aboard the crazy train. You gotta see it ... right in the middle of LAX, Davis spewed a theory about Obama using celeb scandals as a “distraction” ... while he screws us out of our freedoms. Por...